The present invention relates to a process and apparatus for emulsifying two or more immiscible substances.
Certain combustion characteristics of fuel oil can be improved substantially by emulsifying the oil with water. One reason for this is that current oil atomizing technology produces an oil droplet of a size that requires a quantity of excess air over the stoichiometric needs of combustion. However, a stoichiometric matching of air, oxygen and an oil droplet is a primary determination of combustion efficiency and, to a degree, the heat transfer efficiency of a furnace. This is because the differential of heat absorption between air and a furnace heat transfer surface causes heat to be carried out of the furnace in the form of elevated flue gas temperatures in the excess air flow. On the other hand, an atomized emulsified fuel oil droplet emulsified in water is reduced to a much smaller size by the violent expansion of the water when the emulsion is exposed to elevated furnace temperatures. This secondary atomization of the fuel oil droplet permits a closer stoichiometric matching of air, oxygen and the fuel oil, and hence a substantial reduction in heat loss due to excess air flow.
However, due to certain limitations in emulsification techniques currently in use, only a fraction of the improved combustion characteristics of fuel oils emulsified with water are achieved in practice. This is because the current state of the art fuel oil/water emulsions, which are 3 to 10 microns in diameter, contain too much water. Since some fuel oil combustion heat energy is expended in the vaporization of the emulsified water particle, and in elevating its temperature to furnace gas temperature, it is clear that a reduction in the water volume would reduce water temperature elevation and heat of vaporization losses accordingly. Since water in the emulsion is spherically shaped, the volume relationship is a cubic function of the diameter. Thus, a 1-micron water particle would contain 1/1000 as much water as a 10-micron particle and 1/27 as much water as a 3-micron particle. A uniform dispersion of 1-micron water particles in the oil droplet should cause secondary atomization at furnace temperatures with 0.1 to 4 percent of the water induced heat losses that occur in state of the art emulsions.
Another limitation of state of the art emulsion devices is their inability to function over a broad range of fluid viscosities. Generally, fluid viscosity variations in state of the art devices result in a varying degree of dispersion and an unpredictable component particle size.
State of the art emulsifiers for example, that taught by U.S. Pat. No. 3,937,445, function by causing the formation of vapor bubbles within a liquid at low pressure regions where the liquid has been accelerated to high velocities. This process is called "cavitation" because cavities form when the pressure of the liquid has been reduced to its vapor pressure. These vapor bubbles expand while they move along with the flow and suddenly collapse when they reach regions of higher pressure. The sudden and violent growth and collapse of these vapor cavities within a liquid cause the intense shearing forces that cause the emulsification to occur.
In view of the above, the principle object of the present invention is to provide an improved process and apparatus for the emulsification of two or more immiscible substances.
Another principle object of the present invention is to provide a process and apparatus that will produce uniform minimum component particle size over a broad range of fluid viscosities. A specific object of the present invention is to proivde a process and apparatus that will produce emulsified water particles that are 1-micron in diameter, or less.
Still another principle object of the present invention is to provide a process and apparatus that will produce an emulsion that is an agglomeration of two or more immiscible substances.
Yet another principle object of the present invention is to provide a process and apparatus that will use a minimum amount of electro-mechanical energy to create small particle size emulsions.
Yet a further principle object of the present invention is to provide a process and apparatus that will optimize process pressure recovery.
Another specific object of the present invention is to provide a process and apparatus that will reduce emulsification production costs and installation modifications to existing facilities.